Epilepsy is a severe and chronic neurological disorder that affects more than 65 million people worldwide. It is characterized by recurrent seizures that occur after an episode of abnormal electrical activity in the brain, causing temporary loss of consciousness, convulsions, or confusion. As a disorder of the brain, it causes devastating abnormal synchronous discharges in the neural areas of the brain. Because of the huge variation in seizure patterns in subjects, patient-specific detection is difficult to diagnose but very crucial for intervention and treatment.
Antiepileptic drugs are the standard treatment for controlling and reducing epileptic seizures, but around 30% of patients cannot be effectively treated with medication. Deep Brain Stimulation (DBS) and Vagus Nerve Stimulation (VNS) therapy is a surgical treatment for people whose seizures are not controlled effectively by medication. DBS and VNS involves sending regular, mild pulses of electrical energy to the brain by implanting electrodes into specific areas of the brain and via the vagus, respectively. The VNS is placed under the skin on the chest wall, and a wire runs from it to the vagus nerve in the neck whereas surgery is needed to implant the DBS in the affected brain area. However, the surgery may lead to internal bleeding, infection, depression, incision scarring and is not effective in newborn/children/ICU-admitted patient group. Moreover, the implantable devices need to be replaced often to avoid infection, making the lifetime of the devices bound not by the battery life, but rather by pernicious caused in the body.
Up to now, there is no patient-friendly solution for seizure detection and stimulation that targets this alarmingly large population. While multichannel electroencephalography (EEG) seizure detection system on chips (SoCs) have been used in medical practice and in research, the existing multichannel EEG SoCs suffer from several limitations.
One limitation of existing multichannel EEG SoCs is that they have a limited number of channels. For example, existing multichannel EEG SoCs present less than or equal to 8 channel SoCs, whereas the American Clinical Neurophysiology Association sets the minimum technical standard recommendation for pediatric EEG of 16 channels with bipolar and referential montages.
Another limitation of existing multichannel EEG SoCs is that they while they may have good accuracy for seizure onset detection with patient specific approach, they lack seizure termination detection. As may be appreciated, seizure termination detection is crucial for medication and stimulation dose control.
Yet another limitation of existing multichannel EEG SoCs is that they involve invasive stimulation. For example, while some existing multichannel EEG SoCs implement an 8-channel closed-loop seizure detection SoC, these existing multichannel EEG SoCs are not patient-specific, and moreover, are invasive.
Experimental studies show that transcranial electrical stimulation (tES) is safe and efficient in reducing seizure frequency in drug-resistant epilepsy. Some systems have shown that a closed-loop tES may dramatically suppress spike-and-wave episodes in a rodent model of generalized epilepsy. While neuro-feedback system using tES for mental health treatment may exist, they lack patient-specificity and have a limited number of channels.
Turning now to FIG. 1, a variation in EEG pattern (as well as the delay between electrical onset and clinical onset) from three different epileptic patients is generally illustrated. Studies have shown that an electrical onset typically prevails a clinical onset by 0.5-10 s. The systems and methods of the present disclosure may include a non-invasive seizure mitigation system that features a SoCs that have both robust real-time, patient-specific seizure onset and termination detection and power-efficient non-invasive tES. Additionally, the systems and methods of the present disclosure also features the first fully integrated 16-channels SoC for seizure onset/termination detection with tES for seizure suppression, which can be potentially integrated in a wearable patch form-factor, thereby overcoming the above mentioned limitations of the available SoCs.
These and other features of the present embodiments will be understood better by reading the following detailed description, taken together with the figures herein described. The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing.